Drilling hole in torque converter for complete drain?

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Hey guys-

I've read a number of threads on here on how to do a complete tranny flush. I was always taught that an easy way to do a complete flush was to drill a small hole in the torque converter and then thread a bolt into the hole when finished. Is this advisable?

-Mike P

[ May 14, 2003, 09:01 AM: Message edited by: Tyrolkid ]
 
No, I wouldn't think so. Most drilled holes will leave metal shavings inside when the drill bit breaks through the metal, and you obviously wouldn't want those circulating inside your tranny. Also, I'd think that installing a bolt could throw the torque converter off balance at high RPMs. This does raise a good question, though: why aren't drain plugs installed in most torque converters?
 
It's actually a factory repair procedure for a GM 350 transmission-- probably others--. There is of course a proper place to drill, so you don't hit something inside. 1/8 inch hole, I think.

The hole is then closed with a closed end, not hollow pop rivet.
 
My advice is to replace the fluid by sucking out as much as possible, or dropping the pan
and replenshing the fluid with a new filter, and if applicable, replacing the in-line filter.

If you look at the lubrication/pressure system diagram of any auto tranny, you will see the TC has oil flow under pressure to cool it and its oil circulates through the rest of the tranny via the oil pump(s).

Do one or two fluid removals and you should have clean fluid in the tranny.
 
The 1973 Ford Galaxie shop manual also recommended drilling a hole and plugging it with a screw whose threads were to be coated with Permatex sealant. Since this involves drilling into the case, the shavings will be thrust out at the drill site. I never attempted it because there's always the possibility, if done incorrectly, it could either damage the TC or result in a leak - especially the pop rivet technique (in which case, if memory serves me correctly, GM then recommended replacing the TC - easy for them to say!). Since the hole is to be drilled at the TC's periphery, there'll be maximum centrifugal force at that point.
 
Agree Ray.

As I recall (from memory), on the GM 700R4 anyway, the front oil pump has a mechanical connection to the torque convertor. Any imbalance in the moment of inertia of the TC could cause an oil pump wear problem and face seal failure.
 
I had that done on my 1979 Chevy 3/4 van. A trans expert did it. Told me at the time he had drilled 100's. He new exactly where to drill and showed me on a cut open converter. I recall he said the trans had to be a normal operating temp for best results, once you drill the hole, you tap the threads right away and let the trans fluid flush out the crap. No way it wcan do any harm as long as there is fluid come out but you have to know what you are doing so as to not hit an internal fin and not drill to deep. Its a messy job, he got doused in hot ATF because it under some pressure.

The van was new at the time, I installed Amsoil synthetic ATF and the van roled on for 5 yrs and then I sold it to a friends kid with over 100,000 miles. Trans never had any problems.
 
Mike,

I have seen it done with my own eyes to someone else's tranny, but would not do it to mine!
tongue.gif


Multiple flushes or fluid replacements replenish the additives and flush the system with new fluid that keeps the crud to a minimum.
 
quote:

Originally posted by ekrampitzjr:
No, I wouldn't think so. Most drilled holes will leave metal shavings inside when the drill bit breaks through the metal,.....


If drilling iron or steel, magnetize the drill bit.


Ken
 
Speaking of strange things. A friend purchased an 1986-7? Olds 88 V8 (last of rear wheel drive cars) from a big used car dealer. He got a warranty with the car. Well one day not longer after he noticed the oil pressure light come on. So he went to the car dealer and they said, we'll fix,no problem. They did and the car was running fine, no problems. He was getting the oil changed many months later when the shop asked him what hap to the oil pan? The auto dealer cut the bottom of the oil pan off to get at the oil pump, they welded it back. Very good welding job and the car lived a long and happy life.

And there the one my boss told me about. A neighbor of his dad was a retired mechanic for a construction company. Well his Ford car died one day in his driveway and would not start again. So he called the Ford dealer to see what could be wrong. Someone told him it could be the fuel pump and its located inside of the tank. They estimated a cost to fix and he was amazed at the cost. So he had his friend go get a fuel pump. He in turn figured where the pump was in relation to the inside of his trunk and cut a hole to get at the pump. Saved hundreds of dollars on labor. btw-Car still wound not start so he calls the Ford dealer again but this time he talks to someone diffenent. Seems he backed into his truck and Ford has a safety (kill) switch that shuts down the fuel supply. Once he reset the switch, it started. Took him several days of work to change the fuel pump and if he would have went into the dealer they would have looked at the switch first. This is the type of person who won't trust anyone else and he knows it all.

[ May 16, 2003, 09:21 AM: Message edited by: Mike ]
 
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